Detection misnomer

[PerpetuallyConfused]

I'll begin by making an opinion statement: I don't believe in the speed of light © as a universal speed limit. I say that with some caveats; I appreciate that the matter we can detect (which makes up about 4% of the known universe according to current understanding) has to obey relativistic speeds, and I appreciate that no light has yet been detected which exceeds the speed of light. My belief derrives from a seemingly obvious oversight: Our current detection methods are based on both light and physical particles (electron microscopes). So how would it be possible to detect something which travels at a much greater speed anyway? The theoretical 'tachyon' has a lower speed limit of the speed of light. If such a particle existed, how would we ever be able to detect it?

 

The first obvious exception to my postulation is a bubble chamber, but this still relies on physical particles as an exposure medium for you to be able to detect particles travelling at various speeds within it. Are there any experiments which are not constrained by the speed of light or by physical particles? If so, what kind of theoretical maximum speed (beyond that of light) would they be able to detect?

 

Anyone?

[MigL]

If a particle like a Tachyon existed, you'd be able to detect it BEFORE you figured out how to do it because it would travel backwards in time and violate causality.

[timo]

Are there any experiments which are not constrained by the speed of light or by physical particles?

Pretty much by definition there are at least no physics experiments that are not constrained by using physical particles, only. Similarly, the mainstream attitude in physics is not to worry about stuff that has no effect whatsoever (regardless whether it violates relativity or not by doing so). The idea "maybe there is something we don't know" is understandable. But if you think it through you'll realize that at least on this abstract level and in the extreme form of being completely void of consequences there's little reason to bother.

[PerpetuallyConfused]

Pretty much by definition there are at least no physics experiments that are not constrained by using physical particles, only. Similarly, the mainstream attitude in physics is not to worry about stuff that has no effect whatsoever (regardless whether it violates relativity or not by doing so). The idea "maybe there is something we don't know" is understandable. But if you think it through you'll realize that at least on this abstract level and in the extreme form of being completely void of consequences there's little reason to bother.

 

I know what you mean; if it doesn't matter then why bother? its that 96%. The rest of the universe that hasn't been accounted for... and dark matter has been too evasive.

 

Another good reason to detect such things is to further the progress of science - if we only cared about what we could realistically expect we'd never have broken the sound barrier...

[timo]

Dark matter does not fall into your "no effect on physical particles" definition (as nothing that is the concern of physics does - but I already tried to explain that in my last post). It is in fact defined as some yet-unknown substance that effects the motion of large-scale astrophysical structures (same for dark energy).

Perhaps you should be a bit more precise what you mean by "physical particles".

[PerpetuallyConfused]

I guess im using broad strokes terminology, I'll try to be precise:

 

Current physics states that any particle or or photon or wavicle or quantum of light has to move, at maximum, at the speed of light.

 

What detection methods do we have to detect particles which are faster than this? how about by orders of magnitude?

 

Its like the chicken and the egg thing. Physics says that these particles, FTL particles, cant exist, but thats current physics. How can we prove the speed of light as a universal speed limit without detection methods that can exceed that speed?

 

Imagine, your holding a speed detection gun that goes up to 10 metres a second, and you measure a car that goes at 11 metres a second. The detector can still only display 10 metres a second, because thats all it can do.

 

Since all detectors are based on light, subatomic particles like electron microscopes, etc, what ways do we have to truly test if something is actually going faster?

[swansont]

I guess im using broad strokes terminology, I'll try to be precise:

 

Current physics states that any particle or or photon or wavicle or quantum of light has to move, at maximum, at the speed of light.

 

What detection methods do we have to detect particles which are faster than this? how about by orders of magnitude?

 

How do they interact?

 

 

Since all detectors are based on light, subatomic particles like electron microscopes, etc, what ways do we have to truly test if something is actually going faster?

 

 

We have detectors that detect light. We have detectors that detect charge. There are detectors that interact via the weak interaction and detect neutrinos. You can build a detector based on how the particles interact. If the particles don't interact via the known forces, we can't detect them. But such particles don't affect us, because we only interact via these forces.

[timo]

If the particles don't interact via the known forces, we can't detect them. But such particles don't affect us, because we only interact via these forces.

Now that is in fact not true, and subtly different from "if these particles do not interact with normal matter in any way". It is well possible that yet-unknown particles interact with known matter via a yet-unknown mechanism (*). Sadly, by their very nature not much is known about unknown mechanisms.

 

 

(*): Or that known matter interacts with an additional unknown mechanism or that unknown particles interact via a known mechanism.

[PerpetuallyConfused]

Im not saying that I do, or that I know the answer, that's why im asking the question. If we wanted to push the boundary of detection possibilities beyond the speed of light, how would it be done? does the technology already exist, and how many orders of magnitude can the systems take?

[timo]

A particle that moves faster than the speed of light but otherwise behaves like a cannon ball can be reliably detected with a solid brick wall. In that sense, the technology to detect objects that move faster than the speed of light does exist.

 

EDIT: On 2nd though, you probably meant the possibility to measure the particle's speed. You'd certainly need at least two brick walls, well synchronized GPS signals, and properly connected cables for that. The point that Swansont already made remains: The detection possibility depends not only on an objects speed, but also on the type of interactions it has.

Edited March 29, 2012 by timo

[PerpetuallyConfused]

Ok that makes some sense, so we still enter into a chicken and egg scenario but now with not knowing how 'unknown theoretical possible particles' would interact - if it isnt through charge, which i presume could be detected through electromagnetic fields and such, would mass be a detection method? are there others?

 

Since this is a chicken and egg scenario with a high level of speculation, I wonder how we'd be able to move past that barrier. The first thought will be, "why bother to try and detect something you dont know exists?" but I only have to point to the higgs and the LHC to speculate how useful finding as yet unproven particles are. The biggest difference is that, through theoretical models we know that the higgs might exist, and so we know to look for it.

 

Could a theory ever be designed to include such particles I wonder...

Edited March 29, 2012 by PerpetuallyConfused

[swansont]

Could a theory ever be designed to include such particles I wonder...

 

Considering that there was a time when none of the interactions had a theory to explain them, I would say the answer is yes.

 

Now that is in fact not true, and subtly different from "if these particles do not interact with normal matter in any way". It is well possible that yet-unknown particles interact with known matter via a yet-unknown mechanism (*). Sadly, by their very nature not much is known about unknown mechanisms.

 

 

(*): Or that known matter interacts with an additional unknown mechanism or that unknown particles interact via a known mechanism.

 

Fair enough. But we don't have evidence of such interactions.